Constructed in the mid-1920s, the Hilton Orrington Parking Garage is a stand-alone parking structure located adjacent to the Hilton Orrington Hotel in Evanston, IL. Its interior concrete had degraded due to the corrosive action of chlorides, such as salt, and natural life-cycle deterioration to the point where falling concrete was posing a safety hazard to visitors.

The original scope of work included renovating the interior of the four-deck garage; demolition and replacement of deteriorated concrete ramps, columns and beams; as well as ancillary HVAC, electrical and fire alarm work necessary to bring the facility up to current codes.

James McHugh Construction Co. acted as the general contractor on the $3.3 million project, in tandem with design engineer CTL Group and key repair contractor Western Specialty Contractors – Chicago Concrete Restoration branch.

The restoration team faced several unforeseen challenges on the project due to the garage’s advanced age and deterioration. Further complicating the project, the hotel owner also requested that the garage not be shut down for extended periods of time during the restoration, plus the garage’s first floor was occupied by several small businesses, so construction noise, dust and disruption also had to be kept to a minimum.

“Despite the need for repairs, the continued operation of this parking garage was determined to be key to the successful operation of the adjacent hotel. Therefore, the garage could not be shut down for extended periods of time, and could not go off-line for materials to be removed and replaced,” said Steve Genovese, Western Chicago Concrete Branch Manager. “Occupant safety was also a top consideration since construction activities could dislodge concrete spalls above the ceilings in the occupied spaces. Plus, the owner only allowed ‘noisy’ repairs to be performed three days a week.”

As a result of multiple generations of previous, un-engineered repairs to the structure, additional un-foreseen restoration of the steel sub-structure was required, further complicating the project.

Excavated openings revealed unattached amalgams of various types, sizes and arrangements of reinforcing steel in each opening. This required repair excavations to grow significantly in order to uncover sound reinforcement and concrete, said Genovese.

Western Specialty Contractors worked closely with the general contractor and engineer to coordinate excavations with repair evaluations since each opening required custom engineering to address the uncovered conditions.

“The repair locations were quite large, resulting in on average close to 20 yards of concrete material, or two truckloads, for each patch,” said Genovese. “On average, eight workers were onsite for the duration of the project, mainly because only certain sections of the garage were allowed to be repaired at a time. The deck is four levels, with the first two levels still needing availability for parking, and where most of the repairs were found.”

The restoration team was able to devise some creative solutions to keep the project running smoothly, such as eliminating a portion of the topside and underside repairs to a true full-depth repair, along with phasing. The aging, cast-in-place 8″ to 10″ concrete slabs circumvented doubling the project schedule even though the repair quantities doubled.

Despite the challenges, only three months were added to the original six-month schedule due to collaboration by the entire project team.

“The project posed substantial obstacles including technical, emission control and personnel safety. Changes to concrete and steel conditions drove quantity increases during the work, requiring close and timely coordination with the design engineer,” said Steve Bush, Superintendent, James McHugh Construction Co. “The stacked configuration of the parking ramp mandated stringent safety precautions during demolition and repair. Work was completed without injury to staff or reportable emissions from the garage.”

Family-owned and operated for 100 years, Western Specialty Contractors is the nation’s largest specialty contractor in masonry and concrete restoration, waterproofing and specialty roofing.